I'm hoping I can figure out what this noise is since it's coming from the right side. Here's 2 videos of it. Doesn't do it all the time. But always in gear when very slow or stopped. Never in neutral or park. 2008 xb, 225k miles.

 

Sounds to me like the engine revs are dropping into the vibration zone. When you shift to neutral it goes away right?
Congrats that this is only happening now at 225K miles.
Alleged cures cover the spectrum from cleaning the MAF sensor to finding a vacuum leak to not pressing on the brake pedal, engine mounts... the list goes on.
Easiest cure? Shift to neutral at lights and keep your hand on the shifter so you remember to re-engage just before the light goes green

 

Have someone sit in the car with engine running while the transmission is in gear.........open the hood and then firmly grab the air filter housing to see if that stops the sound......a few times that has been the problem with a few of these cars that came in the shop.

The fix was to replace the rear motor mount.

 

Yeah, sounds like mine did when the motor mounts were worn out.